Hydraulic jointing press

ABSTRACT

A hydraulic jointing press having a housing with jaws at one end thereof. The other end is expanded to house a large diameter piston to apply the jointing pressure, the large piston having a smaller piston therein to return the main piston.

United States Patent [191 Lines Jan. 22, 1974 4 54] HYDRAULIC JOINTINGPRESS 1,296,139 3/1919 Thompson 72/453 1 6 l 4 [75] Inventor: Raydon A.Lines, Elizabeth West, 8/196 B 72/ 53 walla FOREIGN PATENTS 0RAPPLlCATlONS [73] Assign: hdush'ies 777 22s 11 1934 France 72/453Elizabeth West, Australia 22 F! d: M 17 1972 1 e ay PrimaryExaminer-Richard J. Herbst PP 254,298 Attorney, Agent, or Firm-Kinzerand Dorn [30] Foreign Application Priority Data May 19, 1971 AustraliaPA 4935/71 [57] ABSTRACT U-S. Cl. A hydraulic jointing press having ahousing with jaws lnt. at one end thereof The other end is expanded to[58] Field of Search 72/453 house a large diameter piston to apply thejointing pressure, the large piston having a smaller piston [56]References Cited therein to return the main piston.

UNITED STATES PATENTS 2,753,917 7/1956 Guthmann 1. 72/453 5 Claims, 2Drawing Figures PAIENTED JAN 22 m4 sum 2 or 2 HYDRAULIC J OINTING PRESSThis invention relates to an improved jointing press and in particularit relates to a press of the type which can be used for pressing asleeve on to electrical lines where the wires require to be joined andwhere they are of a nature such, as aluminium, that soldering or similarmeans are not practicable.

BACKGROUND OF THE INVENTION It is customary to provide hand tools forcompressing the sleeves on to wires which are to be joined, and as suchtools require a very heavy force to give the necessary crimping ordistortion of the sleeve to ensure an adequate hold as well as effectiveelectrical transmission, it has been proposed heretofore to usehydraulic presses which have required very high pressure lines to beable to exert the necessary crimping force on the joining sleeves, thisforce required being, for instance, approximately 24,000 pounds.

To achieve forces of this magnitude in hand held tools by hydraulicmeans it has been necessary to use hydraulic amplifiers to bring theworking pressure of the supply device to this value.

SUMMARY OF THE INVENTION It is the object of this invention to providean improved form of device in which relatively low pressure will be ableto supply the necessary pressure and this is achieved according to thisinvention by utilising a member which has on it one of the jaws andmaking the other jaw movable and guided by this member but instead ofsupplying hydraulic pressure in the normal manner, the device has alarge area cylinder in which a piston of relatively great area iscarried, hydraulic return means being provided in the piston to returnthe piston to'its initial position.

In this way by utilising a large piston in an expanded section of thehousing and providing return means for the piston, low pressurehydraulic medium can be fed into the cylinder and because of thesubstantial area of the piston a sufficient force can be generated togive the necessary pressure to effectively close the sleeve onthe-wires.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectionview of the device along the lines l-l of FIG. 2,

FIG. 2 is an end view taken generally along the lines 2-2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The actual device can besomewhat varied in its construction, but preferably comprises acylindrical housing 1 which has at its operative end a portion 2 whichis shaped to house the jaws 3 and 4 remote from the cylinder, the jaw 4being fixed while jaw 3 is guided to move toward or away from fixed jaw4 by means of a push rod 5 which terminates in one end in means wherebythe jaw 3 can be locked to the push rod 5 by a pin 6. At the other endthe rod 5 is attached to a piston 7 having a diameter much greater thanthe diameter of the housing which of course requires to be of a sizesuch that it can conveniently be held in the hand or if this is not sothen it should be provided with a piston grip or the like whereby thedevice can be operated.

A cylinder 8 is formed on the end of the housing I and has a diametersubstantially greater than the housing diameter and preferably has acrosssectional area which is perhaps six or seven times as great as thecrosssectional area of the housing so that for instance by theapplication of a pressure of 1,500 pounds per square inch a closingforce on the jaws is exerted of perhaps 24,000 pounds.

The piston 8 is connected to the push rod 5 which actuates the movablejaw 3 and as the jaw 3 does not require to have a very great stroke,obviously the expanded end which forms the cylinder need only be ofshort length just sufficient to accommodate the piston and its movement.

The jaws 3 and 4 of course are preferably of a size such that they cantake a series of half section members which can be slid into the jaws tobe held by an appropriate inwardly projecting edge 9 and spring loadedplunger 10 so that different size members or liners can be placed intothe jaws to allow the clamping of sleeves or ferrules of different size,depending of course on the dimensions of the wires being joined.

The hydraulic means for returning the piston 7 includes a further orreturn piston l l. The further piston 11 can conveniently comprise asmaller piston inserted into a cylinder 12 formed in the main piston 7and the return piston 11 will suffice in that a small force only isrequired to return the main piston 7.

The main piston 7 is attached at one side of the piston to the push rod5 which operates the jointing press, while the other side of the pistonis formed with the cylindrical chamber 12. The return piston 11 operatesin its cylindrical chamber 12 and is attached to a stationary piston rod13 which projects through the end of the cylindrical housing 8. Anannular cap 14 fits slidably on this piston rod 13 and is fitted to andis rigidly attached to the main piston 7 to close the cylindricalchamber 12, this annular cap 14 forming a continuation of the piston 7.

The stationary piston rod 13 is formed with two parallel hydraulic fluidpassageways extending along its length, one of these passageways beingthe return passageway l5 and opening into the cylindrical chamber 12between the return piston 11 and the cap 14 while the other passagewayis the supply passageway 16 and opens into a space between the mainpiston 7 and the housing 8.

Hence when pressure is supplied. to the supply passage 16 fluid pressureis applied between the main piston 7 and the housing 8 to operate thepress, the main piston 7 and its cylindrical chamber 12 sliding relativeto the fixed return piston 11. To return the main piston 7 pressure is'applied by the return passageway 15 through the space between the returnpiston 11 and the cap 14 on the main piston 7. As the return piston 11is fixed the main piston 7 is thus moved to its return position.

Suitable sealing means such as O-ring seals are provided on the pistonsand between the cap and the piston rod and also between the piston rodand the opening through the housing through which the piston rod passes.The piston rod is located by any suitable means such as a circlip 17 orthe like.

A control valve 18 is provided on the piston rod 13 extending throughthe housing 8, this valve 18 being hand operated. For convenience thecontrol valve 18 and its operating member 19 extend at right angles tothe piston rod 13 and is so mounted that the valve 18 and operatingmember 19 can be rotated as a unit about the axis of the piston rod 13so that it can conveniently be operated in various awkward situations.The control valve is such that an operation of its control member 19 bythe handle 20 rotatable on pin 21 mounted on support arm 22 fixed to thevalve, the valve will selectively direct the fluid pressure to eitherthe supply passage 16 or the return passage and simultaneously exhausteither the return passage 15 or the supply passage 16 so that operationof the press is achieved.

The control valve [8 includes a boss 23 surrounding the piston rod 13,suitable passages 24, 25 being provided therein to conduct the hydraulicfluid to the hydraulic piston rod 13. The passages in the piston rod 13terminate in circular passageways 26, 27 spaced along the piston rod 13so that the control valve and operating handle may rotate about thepiston rod. Alternatively the piston rod 13 and the control valve 18 maybe rigidly joined together, the rotation being achieved by allowing thepiston rod 13 to rotate in the end of the enclosed housing 8.

The valve 18 comprises a piston member 28 having grooves and lands todirect the fluid from inlet passage 24 to either passage 25 or 25a andto exhaust from passages 25a and 25 as desired, through exhaust passagesnot shown to an exhaust line. The control valve is conventional and neednot be described in detail.

Referring to FIG. 2 the piston member is biased into its centralposition by a coil spring 29, the spring acting between washers 30 and31. A stud 32 having a shoulder 33 is attached to the end of the piston28, the

' washer 30 bearing against the head of the stud 32 and against shoulder34 on cap 35, while the washer 31 bears on the end of the piston 28 andalso against the valve housing at 36.

ln this condition the valve piston is centralised. By moving the valvedownwardly the piston 28 moves washer 31 against the spring 29, thewasher 30 bearing against shoulder 34 so that the spring 29 applies arestoring force on the piston 28. Similarly if the piston is movedupwardly the head of stud 32 moves washer 30 to compress the spring 29against washer 31 which bears on the shoulder 36.

From the foregoing it will be realised that because of the provisions ofan expanded end on the housing which can take the relatively largepiston in the cylinder formed in the housing, a unit is provided whichdoes not require a power amplifier and then simply comprises a movablemember which has at its one end the movable jaw and at its other end thepiston the piston being returned hydraulically by a further piston thusensuring a light weight structure which can easily be handled and whichoperates on a relatively low hydraulic pressure.

I claim:

1. A portable, hand-held hydraulic jointing press comprising astationary jaw and a movable jaw, a push rod connected to the movablejaw, a cylinder-like housing surrounding the push rod, said housinghaving an enlarged cylindrical portion closed at one end andconstituting a main cylinder of cross-sectional area at least severalmultiples of the remaining cross-sectional area of said housing, a mainpiston mounted in said main cylinder, said main piston having a cylinderof smaller diameter and being connected to the push rod so the fluidunder pressure supplied to the main cylinder will advance the push rodto close the jaws, the smaller cylinder having a return piston mountedtherein, means closing one end of the smaller cylinder to define areturn cylinder for the return piston, and means to selectively directfluid under pressure to the main cylinder or return cylinder.

2. A hydraulic jointing press as defined in claim 1 wherein the returnpiston is stationary and has a piston rod extending through a capforming the means closing the end of the return cylinder, the piston rodhaving a pair of longitudinal passages for operating fluid therein, oneopening into the main cylinder and the other into the cylindricalportion of the return cylinder between the return piston and the cap.

3. A hydraulic jointing press as defined in claim 2 wherein the means toselectively direct fluid pressure includes a control valve mounted onthe end of the stationary piston rod, the control valve being operatedby a linkage connected to a handle by which the control valve isoperated and the jointing presses manipulated, the control valve beingconnected to the piston rod whereby the control valve, piston rod andreturn piston are rotatable relative to the-main piston.

4. A hydraulic jointing press as defined in claim 2 wherein the means toselectively direct fluid pressure includes a control valve rotatablymounted on the piston rod, the longitudinal passages in the piston rodopening into circumferential grooves on the piston rod, the controlvalve having passages connecting to the grooves and having an operatinghandle whereby the control valve and operating handle are rotatablerelative to the piston rod.

5. A hydraulic jointing press as defined in claim 2 wherein the means toselectively direct fluid pressure includes a control valve housing and avalve piston, the valve piston having lands and grooves to selectivelydirect fluid pressure from an inlet to the cylinder of the main orreturn piston and to exhaust the other cylinder, the valve piston beingbiased into its central position by a spring acting between spacedwashers each adapted to bear on a portion of the valve piston and thevalve housing.

1. A portable, hand-held hydraulic jointing press comprising astationary jaw and a movable jaw, a push rod connected to the movablejaw, a cylinder-like housing surrounding the push rod, said housinghaving an enlarged cylindrical portion closed at one end andconstituting a main cylinder of cross-sectional area at least severalmultiples of the remaining cross-sectional area of said housing, a mainpiston mounted in said main cylinder, said main piston having a cylinderof smaller diameter and being connected to the push rod so the fluidunder pressure supplied to the main cylinder will advance the push rodto close the jaws, the smaller cylinder having a return piston mountedtherein, means closing one end of the smaller cylinder to define areturn cylinder for the return piston, and means to selectively directfluid under pressure to the main cylinder or return cylinder.
 2. Ahydraulic jointing press as defined in claim 1 wherein the return pistonis stationary and has a piston rod extending through a cap forming themeans closing the end of the return cylinder, the piston rod having apair of longitudinal passages for operating fluid therein, one openinginto the main cylinder and the other into the cylindrical portion of thereturn cylinder between the return piston and the cap.
 3. A hydraulicjointing press as defined in claim 2 wherein the means to selectivelydirect fluid pressure includes a control valve mounted on the end of thestationary piston rod, the control valve being operated by a linkageconnected to a handle by which the control valve is operated and thejointing presses manipulated, the control valve being connected to thepiston rod whereby the control valve, piston rod and return piston arerotatable relative to the main piston.
 4. A hydraulic jointing press asdefined in claim 2 wherein the means to selectively direct fluidpressure includes a control valve rotatably mounted on the piston rod,the longitudinal passages in the pistoN rod opening into circumferentialgrooves on the piston rod, the control valve having passages connectingto the grooves and having an operating handle whereby the control valveand operating handle are rotatable relative to the piston rod.
 5. Ahydraulic jointing press as defined in claim 2 wherein the means toselectively direct fluid pressure includes a control valve housing and avalve piston, the valve piston having lands and grooves to selectivelydirect fluid pressure from an inlet to the cylinder of the main orreturn piston and to exhaust the other cylinder, the valve piston beingbiased into its central position by a spring acting between spacedwashers each adapted to bear on a portion of the valve piston and thevalve housing.